U.S. Pat. No. 4,055,179 discloses a two-piece valve comprising a first tubular member which is connected to the interior of a urine collecting bag at one end and at the opposite end comprises an inner tapered valve seat. A second tubular member is axially slidably positioned about the first tubular member and comprises an inner valve body. When the second tubular member is displaced, the inner valve body can be moved between a position in which it sealingly engages the valve seat inside the first tubular member so as to shut off the valve, and a position in which the valve is open. The valve of this U.S. publication and other known corresponding valves are, however, encumbered with the draw-back that the handling of the valve requires two hands, i.e. one hand gripping about the first tubular member and the other hand gripping about the second tubular member so as to open and close the valve.